This invention relates to an apparatus for removing smoke, mist and other particles generated by machine tools during a machining operation.
The advancements to computer numerical control machine tools such as higher spindle speed and high pressure coolant pumps have made an environment problem because the metal working fluid used to cool, remove chips and lubricate tooling creates a very fine mist.
Conventional mist collectors such as centrifugal collectors cannot filter this fine atomized mist without the use of expensive disposable media secondary filters. Other conventional collectors use disposable media filters as the primary filtration method. The problem with these disposable media filters is that they plug up as they collect mist so that the airflow declines each day of operation. The collected mist does not drain out of these filters so that you end up throwing out media filters that are saturated with metal working fluids.
It is well established that electrostatic precipitators work very well in mist applications when the metal working fluid is petroleum oil product. The collected oil mist droplets drain off. the electrostatic precipitator cell to be reclaimed and reused. Most conventional electrostatic precipitator units are large and are connected to several machine tools with ductwork. Most metal working fluids used today are a water-based or synthetic. These water-based metal working fluids can create nuisance arcing problems for electrostatic precipitation filtration because the collected mist shorts the collector section of the electrostatic precipitator, therefore, industry shies away from using electrostatic precipitators in the water-based mist applications.
An object of this invention is to provide a small compact air cleaner that can be directly mounted to a machine tool. Most conventional electrostatic precipitator units are large and are connected to several machine tools with ductwork. This small air cleaner includes 4xe2x80x3 metal mesh impingers to capture the large mist droplets and a small electrostatic precipitator cell to capture the very fine mist, smoke and other particles. This new apparatus includes a variable speed controller so that the airflow can be set at the minimum airflow level that will provide negative pressure within the machine tool enclosure. The slower the air speed through an electrostatic precipitator increases the collection efficiency. Conventional mist collectors do not have speed control so that they end up collecting excessive amounts of mist out of the machine tool enclosure that prematurely plug filters or create excessive maintenance. The combination of the slower air speed through the electrostatic precipitator and the ability to reduce the voltage on the collector section of the electrostatic precipitator allows this new apparatus to effectively capture mist from machine tools that use water-based and synthetic metal working fluids without nuisance arcing that has previously, caused industry to shy away from using electrostatic precipitator technology.